Chevrolet Performance LT1 Mode D'emploi page 3

Positive Crankcase Ventilation (PCV) System
A closed crankcase ventilation system is used in order to provide a more complete scavenging of the crankcase vapors.
Fresh air from the air filtration system (air cleaner) is supplied to the crankcase, mixed with blow-by gases, and then passed
through a crankcase ventilation valve into the intake manifold. There are two ports, one each per valve cover, for wet sump
oiling engines, that need to be connected to the engine air filtration system (air cleaner). There are 3 ports for a dry sump
oiling system. These ports need to be connected somewhere between the Mass Air Flow (MAF) meter and the engine throttle
body. The air for PCV needs to be measured by the MAF, in order for proper engine operation. PCV hose 12670908 can be
purchased to obtain the quick connect fitting, when creating a custom installation for a wet sump oiling system (item 1 in figure
1). For a dry sump oiling system (item2 in figure 1A) will be needed for right side connectors.
Fig. 1
Variable Camshaft Timing
This engine has the ability to vary the camshaft position versus the piston position. If you chose to use the Chevrolet
Performance engine controller kit, then it will vary camshaft timing to improve emission and fuel economy, while still producing
great power.
At idle, for example, the cam is at the full advanced position, allowing exceptionally smooth idling. Under other conditions, the
phaser adjusts to deliver optimal valve timing for performance, drivability and fuel economy. At high rpm it may retard timing to
maximize airflow through the engine and increase horsepower. At low rpm it can advance timing to increase torque. Under a
light loads, it can retard timing at all engine speeds to improve fuel economy.
A vane-type phaser is installed on the front of the camshaft to change its angular orientation relative to the sprocket, thereby
adjusting the timing of valve operation on the fly. It is a dual-equal cam phasing system that adjusts camshaft timing at the
same rate for both intake and exhaust valves. The system allows linear delivery of torque, with near-peak levels over a broad
rpm range, and high specific output (horsepower per liter of displacement) without sacrificing overall engine response, or
drivability. It also provides another effective tool for controlling exhaust emissions.
Engine Oil Pump - Wet Sump Oil System
Engine lubrication is supplied by a variable displacement two-stage vane-type oil pump assembly. An oil control solenoid valve,
controlled by the ECM, mounted to the oil pump provides two stage functionality. The oil pump is mounted on the front of the
engine block and driven directly by the crankshaft sprocket. The pump rotor and vanes rotate and draw oil from the oil pan
sump through a pick-up screen and pipe. The oil is pressurized as it passes through the pump and is sent through the engine
block oil galleries. The variable pressure/flow oil pump must be controlled by the ECM in order to maintain proper lubrication
and minimize excessive oil delivery to the cylinder heads and PCV system. There are several devices on the LT1 that use oil
pressure to maintain proper functionality. The ECM controls engine oil pressure and flow for oil spray piston cooling, variable
valve timing, cylinder deactivation along with crankshaft and camshaft bearing cooling. The default mode for the oil pump is
high flow and high pressure. This can lead to excessive oil consumption thru the PCV system.
Performance Parts LT1 Engine
TITLE
ALL INFORMATION WITHIN ABOVE BORDER TO BE PRINTED EXACTLY AS SHOWN ON 8 1/2 x 11
WHITE 16 POUND BOND PAPER. PRINT ON BOTH SIDES, EXCLUDING TEMPLATES.
TO BE UNITIZED IN ACCORDANCE WITH GM SPECIFICATIONS.
Fig. 1A
19328729
PART NO.
DATE
03JN14 Initial Release - Rocko Parker
13MY16 Revision - Rocko Parker
3
SHEET
REVISION
33
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